CNN reports that the bulletin, prepared by the FBI and the Department of Homeland Security, said that intelligence indicates that anarchists "from New York" were planning on going to Tampa, and possibly attempting to shut down the city's bridges using improvised explosive devices. The alert also warns of similar threats in Charlotte, where the Democrats will hold their convention from Sept. 4 to Sept. 7.

"FBI and DHS assess with high confidence anarchist extremists will target similar infrastructure in Tampa and Charlotte, with potentially significant impacts on public safety and transportation," the alert said, according to CNN.

The agencies warned state and local law enforcement agents to be on the look out for anarchists buying explosive materials, obtaining weapons training, and preparing for fights with other groups they oppose, such as white supremacists.